Polymers are used extensively in the preparation of biomaterials. Certain biomaterials used in the field include biocompatible and/or bioabsorbable synthetic polymers that are composed of monomers having different affinities for water. For example, in certain polymers formed from glycerol and a diacid, the glycerol may be water soluble while the diacid is nearly insoluble. Thus, when biomaterials including these compounds are prepared, the process for such preparation may simply include adding the monomers neatly to a vessel and allowing them to react directly. Such processes may be problematic because the polymerization reaction may be difficult to control and modify. The products of such reactions may have inconsistent properties between batches, resulting in biomaterials that may fail to perform consistently.
One such method is described in U.S. Pat. No. 7,722,894, Wang et al. The '894 patent describes a process for creating poly(glycerol sebacate) via a polycondensation reaction that occurs under a specific identified reaction condition, namely an anhydrous polycondensation reaction carried out at 120° C. and a pressure of 1 Torr or less to yield a colorless elastomer. However, this method and the specific form of polymer that results have numerous drawbacks that restrict or prevent their satisfactory commercial use. Among the drawbacks are that the specific process conditions taught by the '894 patent do not actually yield an elastomer as described, but instead produce a high molecular weight resin. While further curing of this resin outside of the time periods described can in course still yield an elastomer, the conditions of initial polymerization result in a polymer with a high polydispersity that render it unsuitable for commercial production in certain applications, such as those requiring tight control over molecular weight distribution, including controlled release.
Due to these and other difficulties present in the field, there is an unmet need for processes of synthesizing polymeric materials, where such processes allow for control and modification of the polymerization reaction occurring therein. The present invention meets those needs.